Thermal Performance Analysis of Solar Photovoltaic/Thermal Systems Based on Porous Media and Nanofluids

In this study, a solar photovoltaic/thermal (PV/T) system optimized via the synergistic effect of porous media and nanofluids is proposed. The influences of porous media parameters (shape, thickness, and Darcy number) and nanofluid properties (volume fraction and mixing ratio) on the system’s heat transfer (HT) and power generation performance are analyzed by numerical simulation methods. The results show that a rectangular (REC) porous block can significantly improve the thermal performance by enhancing the flow disturbance and solid–liquid HT area when the thickness is 0.5 times of the channel height (s = 0.5H) and the Darcy number is Da = 0.1, and the system comprehensive evaluation criterion (performance evaluation criterion [PEC]) is enhanced by 34% than that of an empty channel. For the mixed nanofluid, the system channel exhibits the best performance when the volume fraction is 3% and the mixing ratio is 75% Al2O3–H2O + 25% Cu–H2O. The optimization of the balance between the thermal conductivity enhancement and the flow resistance yields a 59% PEC increase. The synergistic effect of the porous medium and nanofluid reduces the PV module temperature, and the cooling efficiency is improved by up to 1.65%. The study reveals that the regulation of the flow-HT mechanism can be achieved through the porous structure shape and the nanoparticle mixing ratio, which provides a theoretical foundation and engineering optimization direction for designing energy-efficient PV/T systems.